Sleep mask



FIG. 1 is a rear perspective view of a sleep mask showing the newdesign, the dashed lines form no part of the claimed design;

FIG. 2 is a front view thereof, the dashed lines form no part of theclaimed design;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof, the dashed lines form no part of theclaimed design;

FIG. 5 is a right side view thereof, the dashed lines form no part ofthe claimed design;

FIG. 6 is a top view thereof, the dashed lines form no part of theclaimed design; and,

FIG. 7 is bottom view thereof, the dashed lines form no part of theclaimed design.

CLAIM The ornamental design for a sleep mask, as shown and described.